Early European spaceflight history, manned and unmanned, about 1950-1975

[leovinus]

I have been impressed for example by the archival donation of local aerospace history documents that has occurred to the Huntington museum in Pasadena of which one or two have been shown in exhibitions.

What would a European analogue to this look like ?

The British Library pointed me to Cranfield University, UK, where there are a few more relevant Hawker Siddeley Dynamics documents One is even called "The space tug situation" by HSD, 1971.  Another "Blue streak/Centaur launcher"

Making progress with the study of primary materials to compare MBB vs HSD space tugs. Via a pleasant visit at The British Library, I managed to read a version of the "Phase A Study" "Part 2 Report Presentation" "EUROPEAN SPACE TUG" study by HSD from 1972. This is only one of many at the BL but the others are still unavailable due to a cyber attack last year which destroyed many of their electronic indices. The BL is hopeful to be able to lend more of the older materials later this year again. To be continued.

[Blackstar]

Making progress with the study of primary materials to compare MBB vs HSD space tugs. Via a pleasant visit at The British Library, I managed to read a version of the "Phase A Study" "Part 2 Report Presentation" "EUROPEAN SPACE TUG" study by HSD from 1972.

When was the decision made to not have Europe build the space tug?

[leovinus]

Making progress with the study of primary materials to compare MBB vs HSD space tugs. Via a pleasant visit at The British Library, I managed to read a version of the "Phase A Study" "Part 2 Report Presentation" "EUROPEAN SPACE TUG" study by HSD from 1972.

When was the decision made to not have Europe build the space tug?

Based on this document alone, that would be July 1972. To quote from the Introduction

The Group of European Companies set up in July 1970 for the initial ELDO Pre-Phase A Study has remained together right up to the cancellation of the Phase A Study in July 1972.

and the Summary says

Finally, a presentation has been prepared for the projected discussions at NASA, Huntsville of July 1972.

Both quotes together seem to say that the study was discussed with NASA in July 1972 and then cancelled immediately. I believe I have seen a memo or book with a more detailed discussion which I do not have handy at the moment but will check later.

[Blackstar]

I would not jump to that conclusion. The decision to cancel European participation in the space tug could have been made by the US before the study contract itself was canceled. It might only be a matter of days, but I suspect that the European study members were the last ones to know.

[leovinus]

I would not jump to that conclusion. The decision to cancel European participation in the space tug could have been made by the US before the study contract itself was canceled. It might only be a matter of days, but I suspect that the European study members were the last ones to know.

You are correct. Am still checking details and our earlier discussion on the end of the tug date in the Agena thread and here and here. It all comes back to meetings in '72 and budget FY71 in the USA. The chronology inthis post as spacelab3.png is very helpful as well.

In addition, we have a quote from "A History of the European Space Agency 1958 – 1987, Volume I, The story of ESRO and ELDO, 1958 - 1973", J. Krige and A. Russo at pages 367 and 368.

It quickly emerged that it would be precipitate to meet in July, as originally envisaged. The nature of Europe's participation in the post-Apollo programme was one reason for the delay. On 5 January 1972 Nixon had approved the space Shuttle programme. At the same time post-Apollo had undergone major changes. The space station concept had been radically altered and its development put back to after that of the Shuttle. The design of the Shuttle itself had been changed, leaving only parts of it really reusable, and the elements in which Europe could participate were reduced from twelve to five. To clarify matters the Ministers agreed that a high-level European delegation should visit NASA in June. There, to their amazement, the tug was withdrawn, the number of Shuttle elements was reduced even further to four, all of relatively minor technological interest to Europe, and "the talks on European participation - which was still desired - were suddenly focussed on the sortie module alone" 1097 This was a Shuttle-borne, shirt-sleeve environment laboratory for scientific research under low-gravity conditions in fields like biomedicine and materials science. Work on the tug was stopped, Shuttle technology studies were wound down and ESO immediately intensified its work on a European sortie module concept in consultation with NASA.

We could argue that the faith of the European tug was taken probably determined on January 5th 1972 as collateral damage of all post-Apollo changes in the US. Am still looking for a "smoking gun" American memo from that time which says clearly "do not fund any tug including the European collaboration". Or maybe "do a spacelab instead of a tug". The decision itself was in June per our earlier discussion which said 14 to 16 June 1972 as for the decision to end the European tug in the report " HAEUI, CSE/CS (72)15, Report of the ESC Delegation on discussions held with the US Delegation on European participation in the Post-Apollo programme, 22 June 1972.". We could speculate that the new HSD engineering document, July 1972 was the date the engineers got the word and documented the cancellation. It would also explain why the JBIS article "The European Space Tug: a Reappraisal" from 1981 says "terminated in July 1972".

The fun continues with more digging to find the "smoking gun memo" in the period January to June 1972.

[Blackstar]

We could argue that the faith of the European tug was taken probably determined on January 5th 1972 as collateral damage of all post-Apollo changes in the US. Am still looking for a "smoking gun" American memo from that time which says clearly "do not fund

What I remember is that it was the US Department of Defense that said no to the Europeans building the tug. The reason was that they did not want a non-American company in the critical path for the shuttle ("critical path" was a term referring to anything that was vital for the shuttle to achieve its mission).

My guess is that there was some kind of joint NASA-DoD shuttle coordination meeting where DoD objected to the Europeans building the tug. This is probably documented, maybe in Spires' book on USAF space transportation.

https://www.maxwell.af.mil/News/Display/Article/3053973/air-university-press-releases-single-volume-overview-of-afs-space-launch-support/

[Blackstar]

This is probably documented, maybe in Spires' book on USAF space transportation.

https://www.maxwell.af.mil/News/Display/Article/3053973/air-university-press-releases-single-volume-overview-of-afs-space-launch-support/

I'll save you the trouble. I just looked in there and he does not have that info.

[leovinus]

We could argue that the faith of the European tug was taken probably determined on January 5th 1972 as collateral damage of all post-Apollo changes in the US. Am still looking for a "smoking gun" American memo from that time which says clearly "do not fund

What I remember is that it was the US Department of Defense that said no to the Europeans building the tug. The reason was that they did not want a non-American company in the critical path for the shuttle ("critical path" was a term referring to anything that was vital for the shuttle to achieve its mission).

Indeed, the story continues and the plot thickens. I have found a chronology of memos from the US State Department which cover the relationship between the USA and Europe regarding STS, Spacelab, Tug and Launch vehicles for the relevant period of January to July 1972. The document numbers are roughly 52391 through 52409 which you can find at either
https://2001-2009.state.gov/documents/organization/xxxxx.pdf 
or
https://web.archive.org/web/20090206191633/http://2001-2009.state.gov/documents/organization/xxxxx.pdf
or via a query like
site:2001-2009.state.gov/documents kissinger apollo europe June 1972 tug

Just replace the xxxxx with a number. There are almost consecutive and make fascinating reading.

The "smoking gun" memo is 52406.

Leaving out the whole lead-up about uncertainty of technology transfer to Europe, launcher discussion, telco sats, etc we can start to discuss the European tug cancellation on April 29th, 1972 where the Secretary of State, William P. Rogers writes to President Nixon on "Post-Apollo Relationships with the Europeans". On April 29th, 1972, William P. Rogers in memo 52405, voices his concern on a change in US policy. He says that the US views on European participation in the STS has begun to harden and the Tug might be too difficult for Europe to build. Elsewhere we see hints that the US became concerned about the cryogenic stages technology transfer to Europe. The European budgets discussed are too small for success as well. Therefore he suggests to the President in (2) that the European Tug should be deferred but in (1) that the Shuttle cooperation should be encouraged.

On May 18th, 1972, President Nixon the White House via Presidential Science advisor Edward E David Jr. writes memo 52406  on "Post-Apollo relationships with the Europeans" to Kissinger and Peter Flaningan and says "I am opposed to European development of the tug"

Next, in 52408 the Secretary of State William P. Rogers writes to NASA administrator James C. Fletcher on June 1th, 1972. It says "The President has carefully studied the rationale and recommendations of your memoranda of April 29, 1972 and May 5, 1972 respectively, and nas decided." and "3. That the Tug should be U.S. - built." and "4. That future joint programs should stress joint payload and utilization activities and that joint development and production in the non -payload area nor be undertaken.".

This leads to July 12th, 1972, memo 52409 from Hermann Pollack, who would talk with the Europeans at ESC meetings, to the acting Secretary. He says "The President did not accept their recommendations fully". That seems to refer to the fact that NASA was ok with sharing tech with Europa but the President (maybe based on other input from Kissinger at NSC?) decided otherwise. He also says "that the space tug to be used by the Shuttle to be US build and I believe this view is shared by most of the interested agencies." as well as "I believe we can terminate such negotiations and discussion of the tug and should point out in so doing that our further review of these tasks reveal that they would lead to excessive additional costs and management complications that the U. S. 1s unwilling to accept.". That is fairly clear and the decision to cancel the tug was taken.

To summarize, this seems to says that the European Tug died on May 18th, 1972 after a decision of President Nixonthe White House on the US side. The European side documents shows that they know on June 22th, 1972 ESC-637 "Tug is out as American position has changed" followed by official cancellation from the Europa side on July 7th, 1972 as documented here. You do need a login on archives.eui.eu/ to read the PDFs though.

My guess is that there was some kind of joint NASA-DoD shuttle coordination meeting where DoD objected to the Europeans building the tug. This is probably documented, maybe in Spires' book on USAF space transportation.

That seems likely. Have not found such a memo yet to lead the President to say "no" on the tug on May 18th, 1972 but will have have another look.

EDIT: to reflect that the May 18th memo is from the White House science advisor and not the President himself

[Spiceman]

Excellent research about the US events in spring 1972. As for Europe... (I thought I had already posted it before, elsewhere. Whatever. A history of ESA, published in 1987. Page 396 of the pdf.
- Or maybe I just forgot I had already posted it.)

As for the development cost of Europa IIIB, this was estimated at 470 MAU plus a 20% contingency,
which took the total to 565 MAU (or FF Delta38 million) at spring 1971 prices and exchange rates.
The German delegation found this far too expensive, and demanded that a number of alternative
configurations without a cryogenic upper stage be studied. All of these so-called low-cost solutions
came out more expensive than Europa IIIB, however. In addition, they posed problems of
geographical return and, since Germany suggested making using of solid fuelled boosters developed in
the French Military Programme, raised issues of technology transfer, access by foreigners to French
industry, and so on.1213

Defeated, in June the ELDO Council decided to abandon the idea, and to pass
the whole question of Europa III on to a Ministerial meeting then being planned.1214

Ministers met informally on 19 May 1972 to plan this gathering.1215 It quickly emerged that a meeting
in July, as originally envisaged, would be much too early. The nature of Europe's participation in the
post-Apollo Programme was uppermost in their minds. On 5 January 1972, Nixon had approved the
space Shuttle Programme. Around that decision, between December 1971 and February 1972 the
Programme had undergone major changes. The space station concept had been radically altered and its
development put back to after that of the Shuttle. The design of the latter had also undergone major
changes, resulting in only parts of it being really reusable, and the scope for European participation
being reduced from 12 elements to five. If in 1971 NASA had strongly encouraged the Europeans to
be involved in the space tug – intended to carry a payload from the Shuttle up to geostationary orbit –
now they were beginning to suggest that they might like to participate in the development of the sortie
module, a Shuttle-borne, shirt-sleeve environment laboratory for scientific research.

 To clarify matters the Ministers agreed that a high-level European delegation should visit NASA in June.

There, to their
amazement, the tug was withdrawn, the number of Shuttle elements was reduced to four, all of
relatively minor technological interest to Europe, and "the talks on European participation which (was)
still desired – were suddenly focussed on the sortie module alone". Work on the tug was stopped,
Shuttle technology studies were wound down and ESRO immediately intensified its work on a
European sortie module concept in consultation with NASA. Final selection was scheduled for
October 1972, whereupon the scheme would be presented to Ministers, who would have to decide if
they wanted to embark on it. 1216

1213 Low Cost Launchers. Conclusions of the Europa III Ad Hoc Group, ELDO/C(72)14 Add, 30 May 1972
(ELDO1561). For the French position see the Annex to ELDO/C(72)19, 29 May 1972 (ELDO 1566).

1214 See minutes of the 57th ELDO Council, 8 June 1972, ELDO/C(72)PV/3, 16 June 1972 (ESC 1545)

1215 The minutes of this Informal Ministerial Meeting - 19th May 1972 are in (ESC 1473).

1216 The quotations are from the Report by the Secretary General of the European Space Conference on the
Status of European Space Programmes, CSE/CM(October 72)WP1, 12 October 1972 (ESC 116)

[Spiceman]

The two posts list of event dates seems to evenly match.

Hence it seems that "decision point" happened over the months of May - June 1972: on both sides of the  Atlantic. Things were going slower back then, in a not-so-connected world.

More seriously, NASA had just secured the Space Shuttle on January 5, 1972 after a truly horrible year: also the first of James C. Fletcher as administrator. Reading Logsdon and Heppenheimer histories, Fletcher and Low truly had steel nerves over that year when though-bargaining the Shuttle fate, shape and cost with Nixon's OMB and PSAC : Caspar Weinberger and Edward E.  David respective organizations: which did not even agreed between them - driving NASA officials a little crazy at times ! October 1971 was case in point, Shuttle almost kicked the bucket that month. PSAC was on the brink of extinction, Nixon shut it down the year after. He had been frustrated with PSAC over the SST and a few other high-tech initiatives. And ran his own science / technology / engineering team of advisors, to David dismay.

But NASA Shuttle troubles were a joke compared to ELDO Europa miseries (F11, November 5, 1971, was a truly pathetic failure. Europa II was now a zombie walking dead, yet not definitively killed until April 1973 when F12 was formally cancelled. Blue Streak had already been shipped to Kourou, ended up cut up as a chicken coop ! Plus Europa III: - which one among five concepts ?).
ELDO and Europa were zombies. France alone, while successfully plotting L3S against Europa IIIB, also had René Aubinière trying to salvage Europa II to launch the infamous Symphonie satellites, flights F13 and F14 circa 1974.  But had Aubinière suceeded in his mission, L3S, future Ariane, might have been postponed or canned altogether. So it was kinda Europa II near term vs Europa IIIB vs L3S, with enough money only for one of the three.

And there was a very real connection between Europa III small hydrolox engine and space tug engine tech. They had common technical ground not only to cut development costs but also because, at least from Germany point of view, Shuttle was to be Europe next launcher after Europa IIIB. Henceforth they would kinda share their upper stage.

It should be noted however than the plain old, non-restartable HM-7, 1960's tech (son of HM-4, CNES 1966 Diamant LH2 studies !) soldiered on for almost 50 years; until the last Ariane 5 flight: in 2023 !
The Space Tug reusable / restartable engine would have been closer from the Vinci - which took 20 years to find its place on the first Ariane 6 flight.
From memory, Germany was gung-ho on extremely advanced hydrolox engines, for Europa IIIB stage 3 as much as for the Shuttle space tug. France and Great Britain however, having labored on the RZ.20 and HM-4 / HM-6 / HM-7 over a decade, were a bit more cautious. LOX was known stuff, but LH2 was a major b*tch.
Out of 7 "Ariane 1 to 44L" failures, 1979-2003, 5 were traced to the HM-7: 1982, 1985, 1986 and twice 1994, January and December altogether. The lower stages of Ariane only had a) a pogo in 1980 and b) the cloth of doom in 1990.

We are back to Germany "US trope" which clashed headon with France gaullist attitude. Which plagued the famous summer 1973 Ministerial Space Councils, though-bargaining L3S (France) against post-Apollo (Germany) against Marots sats (UK).

[leovinus]

Excellent research about the US events in spring 1972. As for Europe... (I thought I had already posted it before, elsewhere. Whatever. A history of ESA, published in 1987. Page 396 of the pdf.
- Or maybe I just forgot I had already posted it.)

Thanks for the context and links! Indeed, we discussed the "history of ESA" document earlier in the Reusable Agena thread where the tug also came up.

For the European side of the tug cancellation, I had a look at the ESC memos 0635, 0636, 0637, and 0654 via the ESA Archives. Very informative but the eye opener for me was the US White House memo by Nixon from May 18th, 1972.

[LittleBird]

Excellent research about the US events in spring 1972. As for Europe... (I thought I had already posted it before, elsewhere. Whatever. A history of ESA, published in 1987. Page 396 of the pdf.
- Or maybe I just forgot I had already posted it.)

Thanks for the context and links! Indeed, we discussed the "history of ESA" document earlier in the Reusable Agena thread where the tug also came up.

For the European side of the tug cancellation, I had a look at the ESC memos 0635, 0636, 0637, and 0654 via the ESA Archives. Very informative but the eye opener for me was the US White House memo by Nixon from May 18th, 1972.

I think the list of topics Aerospace had been asked to study before the cancellation is also v illuminating, see https://forum.nasaspaceflight.com/index.php?topic=11111.msg2588574#msg2588574 from which grab below is repeated.

[LittleBird]

<snip>
On May 18th, 1972, President Nixon writes memo 52406  on "Post-Apollo relationships with the Europeans" to Kissinger and Peter Flaningan . President Nixon says "I am opposed to European development of the tug"
<snip>
 

Surely that memo is from Ed David, not Nixon himself ? https://en.wikipedia.org/wiki/Edward_E._David_Jr.
His name, as head of PSAC, pops up in a space related context quite often in Shuttle, Kennen etc histories iirc.
THe Aerospace studies I mention in previous post must have been an important element of the "further review" he mentions. Surely NRO must have asked a few pointed questions about GEO at some point, perhaps via Aerospace ?

[Spiceman]

Nixon hated the PSAC. He instead took his science advice from a non-official group led by William Magruder, former SST czar. There was a big techno-optimist initiative called NTOP that went nowhere.
https://www.nytimes.com/1977/09/12/archives/william-magruder-headed-sst-project-extest-pilot-and-designer.html

[leovinus]

<snip>
On May 18th, 1972, President Nixon writes memo 52406  on "Post-Apollo relationships with the Europeans" to Kissinger and Peter Flaningan . President Nixon says "I am opposed to European development of the tug"
<snip>
 

Surely that memo is from Ed David, not Nixon himself ? https://en.wikipedia.org/wiki/Edward_E._David_Jr.
His name, as head of PSAC, pops up in a space related context quite often in Shuttle, Kennen etc histories iirc.
THe Aerospace studies I mention in previous post must have been an important element of the "further review" he mentions. Surely NRO must have asked a few pointed questions about GEO at some point, perhaps via Aerospace ?

Great catch! While the memo 52408 from June 1st says "The President has carefully studied ..." the White House memo 52406 from May 18th is indeed signed by Edward David Jr., the Science advisor to the President, and not the President himself.

So the evidence is that the White House cancelled the European tug on May 18th and the June 1st memo confirms it was with the President's blessing. Ok, then we are still looking for an instruction by Nixon himself from before May 18th, and possibly a memo from DoD to the White House with a negative recommendation on the tug before that. Both of which could have been verbally in which case there won't be a record.

[leovinus]

Excellent research about the US events in spring 1972. As for Europe... (I thought I had already posted it before, elsewhere. Whatever. A history of ESA, published in 1987. Page 396 of the pdf.
- Or maybe I just forgot I had already posted it.)

Thanks for the context and links! Indeed, we discussed the "history of ESA" document earlier in the Reusable Agena thread where the tug also came up.

For the European side of the tug cancellation, I had a look at the ESC memos 0635, 0636, 0637, and 0654 via the ESA Archives. Very informative but the eye opener for me was the US White House memo by Nixon from May 18th, 1972.

I think the list of topics Aerospace had been asked to study before the cancellation is also v illuminating, see https://forum.nasaspaceflight.com/index.php?topic=11111.msg2588574#msg2588574 from which grab below is repeated.

Nice find. Do I see that right that this one page is from study NASw-2301, "Analysis of Space Tug Operating Techniques Final Report (Study 2.4) Volume I: Executive Summary" from August 1972? ? The statement "This effort was not expended due to cancellation of the ELDO Subsystem Review Meetings as a result of the termination of the ELDO Tug activities" is pretty explicit and the timing of August 1972 does fit nicely with the other dates we found.

[leovinus]

Came across the book "NASA in the world: fifty years of international collaboration in space" by John Krige. It has a Chapter 3 on "Technology transfer with Western Europe: NASA-ELDO relations in the 1960s" and a Chapter 6 " European Participation in the Post-Apollo Program, 1972: Disentangling the Alliance—The Victory of Clean Technological Interfaces" which discussed the tug et al, roughly pages 113 to 118. The references page 308 attached here points to roughly the same material as we are discussing upthread.

[LittleBird]

Excellent research about the US events in spring 1972. As for Europe... (I thought I had already posted it before, elsewhere. Whatever. A history of ESA, published in 1987. Page 396 of the pdf.
- Or maybe I just forgot I had already posted it.)

Thanks for the context and links! Indeed, we discussed the "history of ESA" document earlier in the Reusable Agena thread where the tug also came up.

For the European side of the tug cancellation, I had a look at the ESC memos 0635, 0636, 0637, and 0654 via the ESA Archives. Very informative but the eye opener for me was the US White House memo by Nixon from May 18th, 1972.

I think the list of topics Aerospace had been asked to study before the cancellation is also v illuminating, see https://forum.nasaspaceflight.com/index.php?topic=11111.msg2588574#msg2588574 from which grab below is repeated.

Nice find. Do I see that right that this one page is from study NASw-2301, "Analysis of Space Tug Operating Techniques Final Report (Study 2.4) Volume I: Executive Summary" from August 1972? ? The statement "This effort was not expended due to cancellation of the ELDO Subsystem Review Meetings as a result of the termination of the ELDO Tug activities" is pretty explicit and the timing of August 1972 does fit nicely with the other dates we found.

Yes, that's the one I had linked to in my post in the Reusable Agena thread. As you say, pretty conclusive.

[Blackstar]

So the evidence is that the White House cancelled the European tug on May 18th and the June 1st memo confirms it was with the President's blessing. Ok, then we are still looking for an instruction by Nixon himself from before May 18th, and possibly a memo from DoD to the White House with a negative recommendation on the tug before that. Both of which could have been verbally in which case there won't be a record.

May not have been anything written. They could have taken the issue to Nixon and it was a verbal order, like you posited.

One place you could look would be in volumes of the Foreign Relations of the United States (FRUS). FRUS can be really addictive. They often contain transcripts of top-level presidential meetings. Nixon was a crook and a deeply flawed man, but he was really smart, and that comes through in the transcripts of his meetings. It makes them interesting reading.

[TheKutKu]

Some information about the H20 engine, developped for Europa 3, from a French perspective, from"La légende d'un demi-siècle de moteurs fusée, L'histoire de Villaroche Nord,1 ere partie,1953-1980", the industry history book about the Villaroche plant of Safran/Snecma/SEP/SEPR (now still part of Safran Aircraft, it doesn't any space activities anymore and therefore isn't in Arianegroup).

Translation:

■EUROPA 3B: THE CRYOROCKET PERIOD AND THE H20 STAGE

On April 15, 1969, the new Europa III B launcher selected by ELDO was a 2-stage launcher. The first with 120 tons of storable propellants and 4 Viking engines, the second with 20 tons of cryogenic propellants and a closed cycle engine with 20,000 daN of thrust. This program was intended to be cuting-edge, because such an engine only existed in the United States at the time. This was in 1969, but the project was abandoned in December 1972 and it is only today, in 2010, that Europe is finally acquiring an advanced technology engine (VINCI engine).

In its concept, the stage included 2 tanks with separate bulkheads. The LH2 tank in the upper part was pressurized with hydrogen taken from the engine and the LOX tank in the lower part with helium contained in spheres immersed in the LH2 tank and heated in the engine pre-chamber beforehand.

To be clear, this H20 stage (pronounced H twenty) was of German design and the engine, which we will also call "H20" had been designed by the MBB company. A GIE (Consortium) called CRYOROCKET (50% MBB, 50% SEP) had been created to carry out this project. As a whole, the engine was completely linear with an in-line turbopump extended by the combustion chamber.

The distribution of responsibilities assigned the turbopump to the SEP and the main chamber to MBB. The "stage" aspects were divided between ERNO, FOKKER, Air Liquide. Functionally, we see that the turbopump consists of an oxygen pump, a hydrogen pump and a pre-chamber containing the turbine that drives the pumps. Before being injected into the pre-chamber, almost all of the LH2 flow is used to cool the combustion chamber and the divergent. Only a small part of the LOX flow is injected into the pre-chamber, so as to provide power to the turbine with a reasonable temperature of 1080 K.
 The mixture thus produced is then injected into the main chamber where it meets the rest of the LOX (the largest part).

Page 2:
Block Diagram (flow in kg/s)
H2 Tank pressurisation
Roll Control

Engine:
Thrust: 20,000 daN
Isp: 448s
Rotation speed: 39,390 rot/min
Mixture Ratio: 6:1
Burn Duration: 448s
Chamber:
Chamber Pressure: 130 Bar
Mixture ratio: 6.4
Gas temperature: 3636k
Flow rate of hot Gases: 11.59 kg/s
Flow rate LOX:  33.41 kg/s

Pumps (LOX/LH2):
P at entry (bar) 3.1 / 2.1
Delta P (bar): 264.9 / 249.3
Flow rate (kg/s): 39.02 / 6.58
Wheel diameter (cm) : 88.6 / 254.7
Power output (KW): 1,468/4,982

Pre-Chamber/Turbine
P Pre-Chamber: 215 Bar
Gas temperature: 1,082K
H2 Flow: 5.97 kg/s (at 160K)
Flow LOX: 5.61 kg/s
Mixture ratio: 0.92:1
Turbine power output: 6,500 KW

Page 3
As early as 1969, SEP therefore began to define this monumental turbopump shown above. The oxygen pump has 1 stage, the hydrogen pump 2 stages, the annular prechamber feeds a single-stage turbine. Since the propellants are not hypergolic, the prechamber (and the chamber) are ignited by a fluorine cartridge. A reserve of GH2 is used to start the turbine.

What work was carried out?

A layout model shown below was used to define the passage of the propellant lines along and inside the thrust cone.

Small-scale tests (HM7)
To better understand the validity of certain options chosen for H20, small-scale tests were carried out in 1972 on the hydrogen and oxygen pumps of the HM7. Thus, on the H2 pump, open-air tests (with the aim of reducing the cost of the tests) demonstrated that it was perfectly possible to establish an air-LH2 similarity of most of the hydraulic characteristics of a hydrogen pump.

Page 4:
On the O2 Pump, different inducers were tested and the performance of a 24-blade Rolls Royce pump was compared to that of a 24-blade SEP pump, without any significant advantage for one or the other emerging.

Above, LOX Input and Output (LOX Input is through the Gimbal), Engine Gimbal is of 5° in all directions
Above, LH2 Input and Output (Prechamber and Chamber are not installed)

Subscale LOX Inducers tests (HM7)

Page 5
Full-scale tests
In 1973, full-scale dynamic tests on the centrifugation bench made it possible to check the performance of the hydrogen pump's flanged wheels.
Similarly, on this bench, a simplified rotor (without blades) was tested in order to identify the first critical speed and the balancing of the rotating assembly.

H2 Wheel Before/After Flangeing

Page 6:
But on December 20, 1972; the project was abruptly stopped, replaced by the L3S which would become Ariane.

Centrifuging bench.

THE ROTOR IS DRIVEN BY HYDROGEN GAS (ONE INLET, 2 OUTLETS) THEN BURNS IN A TORCH.
THE BEARINGS Are standard materials, therefore very different from the final bearings. ARE LUBRICATED BY AN OIL-NITROGEN AEROSOL

SPEED REACHED 42,000 RPM, CRITICAL SPEED: 31,000 RPM.